Chapter 2—The Nuclear Testing Program e 19 Figure 2-3—Drill-Back Operation Drill rig Surfaced a 3 Ny oa Phot credit: Department of Energy “ane of interest Emplacement Tower for Vertical Drill Hole Test 1/2 up to 7 ft; while Livermore typically uses 8-ft diameter holes and an occasional 10-ft diameter hole.2° Livermore usually places its experimental devices above the watertable to avoid the additional time and expense required to case holes below the water table. Whenthe device is detonated at the bottom of a vertical drill hole, data from the test are transmitted through electrical and fiber-optic cables to trailers containing recording equipment. Performanceinformation is also determined from samples of radioactive material that are recovered by drilling back into the solidified melt created by the explosion (figure 2-3). On rare occasions, vertical drill holes have been used for effects tests. One such test, ‘‘Huron King,’ used an initially open, vertical ‘‘line-of- sight’” pipe that extended upwards to a large -~- X-eae cae ce ee nhTillie caer ee my ey come me ee ne se, se cams eon, TE Te ee ee ey oR RY OE GERD Se we ground zero SOURCE: Modified from Michael W. Butler, Pastshot Driling Hancdboc Lawrence Livermore National Laboratory. Jan. 19, 1984, enclosed chamberlocated at the surface. The chan ber contained a satellite inside a vacuum to simula the conditions of space. The radiation from tt explosion was directed up the hole at the satellit The explosion was contained by a series of mecha ical pipe closures that blocked the pipe immediate after the initial burst of radiation. The purpose of U test was to determine how satellites might ! affected by the radiation produced by a nucle explosion. Tunnel tests occur within horizontal tunnels tr are drilled into the volcanic rock of Rainier Aqueduct Mesa. From 1970 through 1988, the 20Livermore has considered the use of 12 ft diameter holes, but has not yet used one.